The influence of neutron irradiation (up to 1.1 x10²² n/cm², E>0.1 MeV) on the creep rupture properties of a Cb stabilized 16Cr-13Ni steel was studied in this paper. Different heat treatments and cold work conditions and several irradiation temperatures were investigated.

Low-temperature irradiation causes an increase in time to rupture at 650 and 750 C, whereas creep rate is reduced by more than a factor of ten. The creep ductility decreased to less than 1 percent. High-temperature irradiation does not cause a substantial change in rupture time at 650 C for the aged condition and the 50 percent cold work and 50 percent cold work+1 h 850 C conditions.

The rupture life of specimens which were cold-worked 10 percent is strongly decreased by irradiation. Only slight changes in creep rate could be observed after high-temperature irradiation. Electron microscopy investigations indicate that the increase in rupture life and reduction in creep rate after low-temperature irradiation is due to a large number of dislocation loops. In the specimens irradiated at 650 C and above only He bubbles could be detected.